Engine hours on RSR sprint engine

[pranqster]

I currently have an RSR sprint engine in my 2002 Cup Car. It was put in by the original owner. Porsche motorsports recommends a rebuild for this engine every 30 to 35 hours.

By my estimation the engine has not quite 45 hours on it. It has been raced only 8 of those hours. I have not had a mechanical overev in the car and the other two owners have told me they did not have any mechanical overevs either.

My query is two fold.

First, does anyone have any knowledge of running a sprint engine to 60 hours or more?

Second, can anyone discuss the merits of a 3.6, 3.8, 4.0 sprint engine versus a 3 ring 3.8 cup engine?

Thank you in advance for the answers.